Apparatus for removing dust from gases



APPARATUS FOR REMOVING DUST FROM GASES Filed March 29, 1949 2SHEETS-SHEET l Marcel Ehl instr ATTORNEY E. MERCER Erm. S 2,603,309

APPARATUS FOR REMOVING DUST FROM GASES Filed March 29, 19492sHEETs-sHEET2 Patented July 15, 1952 APPARATUS FOR REMovlNG DUST FROMGASES Ernest Mercier and Marcel Ehlinger,` Paris, France, assignors, bymesne assignments, to Moore, Inc., Atlanta, Ga., a corporation ofGeorgia Application March 29, 1949, Serial No. 84,144

In France April 3, 1948 V 15 Claims. 1

The present invention has for its object apparatus for removing dustfrom gases which consists in leading the gas into the apparatus at highspeed as a thin layer (about 1 cm. in thickness or even less) andleading it out as a thin layer of substantially the same thickness aftera change of direction of about 180, or at least a very substantial andabrupt change of direction, has been imposed upon the flow of the gas,the mean radius of curvature of the bend being quite Smalli. e. likewiseof the order of one centimetre or even less, whereby considerablemomentums' are set up which tend to hurl the dustv particles conveyedtowards the outside of the bend whereby the desired dust removal isSecured.

The invention is also concerned with apparatus by means of which gasesresulting from the combustion of coal can be purified by removingtherefrom the 'ash and clnker therein, which apparatus is capablenotably of dealing with gases at high temperatures and with gases underpressure. y

Apparatus of this kind should be composed of metal parts that are simplein design, not liable to be deformed by the action of heat and a slightdeformation of which will not be detrimental to their proper operation.In addition,v the dimensions of the apparatus should be small so that nolarge-sizev pressure-resisting casings have to be used where thefseparation is to be effected from gases under pressure. y

Moreover, the units composing the apparatus should be simple and itshould be possible to connectthem in series in order to enhance thecleaning elect or infparallel in order to increase the output.

The unit' of the apparatus according to the invention comprises .adouble channel delimited by plane or substantially plane metal sheets,generally three of themfcomposing an elemental section of the unit;arranged substantially parallel to and at very `small distances from oneanother. The gas to -be,.purified flows rstly throughV the channelicomprised between one of the outer vsheets and the central one, then inthe reverse direction through the channel comprised betweensaid centralsheet and the other outer sheet. As the gas passes from the firstchannel into the second one its direction of ow is deflected through anangle of18() over a bend of very small radius, whereby the removalofathe dust is performed by the action of the centrifugal force upon theparticles. s

Of course, theA passage leading from the first (Cl. 18S-79) channel intothe second one should be so dimensioned in dependency on the characterand size of the particles to beeliminated that a satisfactory operation'of the apparatus is secured.

A first solution of this problem consists in providing a passageforming'the bend continuous with the leading in channel, this passagebeing delimited by a wall that in a particular embodiment may be anextension of either or both of the outer walls, said wall being providedwith one vor several slits suitably located to facilitate. the dischargeof the particles to be removed.

A further solutionconsists inhaving Ythejthree parallel sheet metalwalls with their edges substantially in a plane transverse to the planesof the sheets, the channels therebetween opening freely into a chamberin which the dust is co1-` lected.

A third solution consists in inwardly oisetting from the transverseplane thev edge of the inner or central wall with respect to the edgesof the outer ones in an arrangement which otherwise remains the same asvthe Vsecond solution. A

Units similar to the ones justgdescribed may be grouped in series, alsoby pairs in order to lessen head losses between two successive units.

In another embodiment the lunits may also be arranged radially about acommon axis 'of rotation within a slotted cylindrical coaxial -barrelconnecting them with one another, the median plane of each unit goingthrough said aXis of rotation. The rotor comprising the barrel and theunits may be rotated at high speed, the design' of the inner 'channelsbeing such that the gases to be purified are taken into the apparatus`through the one end plate'of the barrel and out of it through theopposite end plate whilea dust collector surrounds the rotor.

Of course, where the gas to be purified is under pressure, the unitsyshould be arrangedwithina pressure-resisting casing In this case specialsteps should be taken'to avoid the condition that removal of theaccumulated dust is attended with arv loss of4 the lgas under pressure.-Such removal may be effected',y according to lthe invention, by sprayingwater into the apparatus in such a manner that a sludge is formedtherewith that is discharged to the outsidezofthe pressure resistingcasing through a pipe'the diameter and length of which are so chosenthat continuous removal is secured without any risk of. clogging and atreasonably low costs.

Several embodimentsof the present invention are `illustrated by wayv ofAexample in the Vappended drawing.'

Figures 1, 2, 3 respectively show the three aforementioned solutions ortypes of dust-removing units.

Figure 4 is a diagrammatical longitudinal View, and Figure 5 across-sectional view taken on line V-V in Fig. 4, which show adust-removing apparatus comprising a single group formed of a pluralityof units.

Figure 6 illustrates a dust-removing apparatus composed of two groups ofunits in series in opposed relation.

Figure 7 shows a dust-removing apparatus comprising three groups ofunits in series in a different arrangement.

- Figures 8 and 9 diagrammatically show a rotary dust-removing apparatusin lonigtudinal and cross-sectional views respectively.

Figure 1U diagrammatically shows a dust-V removing apparatus forremoving dust from gases under pressure, together with its hydraulicdustdischarging system'.

In the dust-removing unit shown in Fig. l, the dust-laden gas is led inthrough channel I and out through channel 2 as a thin layer. At 3 a bendis formed in which the particles are urged outwardly by the centrifugalforce and tend to escape through a slit 4 into a chamber outside theunit. The channels and the bend are defined by walls made of thin sheetmetal. Experience has shown that if suitably dimensioned and operatedwithsuitable gas flow speeds such a unit possesses a high separatingcapacity which, of course, .is dependent on the character and size ofthe dust particles. The radius of curvature Vof the passage forming thebend is of the order of a. few millimetres or of one centimetre.

According to Fig. 2 the wall dening the bend is dispensed with, and soit is in Fig. 3 in which the side walls extend beyond the middle one.

These elemental units forming U-shaped channels are juxtaposed in anydesired number to deal with any desired gas flow.

FigureV 4 shows a dust-removing apparatus composed of similar unitscontained in a casing or chest and so arranged that the gas flows infrom conduit A5 Yand out to conduit 6 and is deflected through the unitas shown by the arrow. For that purpose a barrier partition or end wall9 is provided which closes the remote ends of the channels through whichthe gas to be puried isvled in from conduit 5 and prevents it fromflowing out directly through conduit B, said partition 9 being aperturedto provide a free exit at this end of the channels through which thepurified gas after sharp reversal of its flow is led out to conduit 6.The entering gas is prevented from entering these reverse now channelsby barrier walls 9 which in the embodiment of Figs. 4. 5, 6 and 7 areinclined to the direction of the entering gas, the Walls between thechannels being of generally triangular shape.

The barrier walls 9, 9 provide means cooperating with the walls of theunits and with the casing to conne the gas to ilow from the inletopening in succession through the channels with reversal of the flowabout the central walls or partitions of the units. The casing,moreover, provides means cooperating with the walls of the units toinsure such gas flow and to effect discharge of the materials suspendedin the gas under the centrifugal force developed by such reversal. Thedust particles settle in a hopper 1 which, if desired, may containbaflles bywhich the dust already deposited is retained and preventedfrom being'whirled up back into the gas flow. A handor power-actuatedrake 8 serves to clean the narrower portions of the channels.

Experience has shown that by providing a fan adapted to sucka smallfraction of the gas from the hopper the efficiency ofrthe apparatus isincreased. This fan 40 forces the more or less purified gas thus tappedfrom the hopper again into the intake 5 of the apparatus.

The dust remover shown in Fig. 6 is composed of two units similar to theone shown in Fig. 4, with the peculiarity that they are arrangedsymmetrically and that their side walls 9 are contigucus. The barrierpartitions 9 retain the gases from flowing directly from the intake 5 tothe outlet 5. ,On the other hand they allow them to rflow from hopper IUinto hopper II.

As shown in Fig. '7, the dust remover comprises three units. It will beappreciated that the dustremoving effect is improved according as thegas passes through alarger number of units, which is confirmed byexperience. The units may have unequal sections so that the flowstherethrough are unequal. They may be arranged one after the other in astraight line or otherwise, e. g. in

a helix.

Figs. 8 and 9 illustrate a dust remover which likewise comprises unitsproviding channels I2, I3 defined by partitions 3|, 32, 33 arranged in arotor driven at high speed. The units are formed so that channels I2, I3are radial. Four of these units are shown in the drawing, yet a lessnumber or a considerably larger number of them may be used if desired.The gas is taken in at the inlet I4 and out at the outlet I5 and itspaths of flow are indicated by the arrows. In the outer portions I6 ofthe channels ow reversing passages are formed in which the centrifugaleffect of the rotation adds to the removing action of the unit which issecured by sharp reversal of direction about the edge of partition 3I.The particles settle in the annularV chamber provided by casing 35 andfall into hopper I'I connected to the bottom of this casing. The casing35 and the walls of the rotor which provide the channels I2, I3cooperate to confine the gas to flow in succession through thesechannels and to be reversed in passing from one to the other so that thecombined effects of reversal and of centrifugal force due to therotation insure the separation of the particles from the gas.

The rotor is driven by means of the shaft I8 that carries a pulley I9and is mounted in bearings 20. Stuffing boxes 2|, 22 or similar devicesare provided to prevent leakage between the separation chamber and thegas inlet and outlet and at the point of passage of the shaft throughthe inlet conduit I 4. The rotor may be keyed on the same shaft as thefan or blower (not shown) which produces the circulationI of the gas. Ifdesired a plurality of rotors may be arranged in series upon the shaftI8 in th'e direction of the gas flow in order to improve the separatingeffect or a plurality of rotors may be arranged in parallel with respectto the gas flow in order to increase the output. Rakes may be providedto clean the narrower portions of the channels. The arrangement may besuch that the gas flows through the rotor either in a generallyascending or a descending or in a horizontal direction.

If the gas to be puried is under pressure, the apparatus is housed in apressure resisting vessel, which is easily conceivable with the rotaryarrangement shown in Fig. l8' if the inlet conduit I4, the casing 35,the hopper I1 and the outlet conduit therefrom are constructed to bepressure resisting. Fig. illustratesa dust remover composed ofstationary units similar to those of Figs. 4, 5 and 6 enclosed in acylindrical pressure-resisting casing or pressure vessel. Thisembodiment is Icomposed by way of example of four units 23 arrangedsymmetrically by pairs. The dust laden gas under pressure enters throughinlet 5 and after passing in series through the units 23 is dischargedunder Ypressure at outlet 6. The dust settles in the hoppers 24.Partitions 25 separate the hoppers and units in the same manner as dopartitions 9 in Fig. 6.

Such a dust remover may be constructed to operate under considerablepressure, i.' e. 100 kgs/sq. cm. or more, and may conne gases at a veryhigh temperature. It maybe arranged within a gasor water-jacketedpressure vessel cooled by a suitbale gas or by water circulated throughthe jacket. l f

If desired the action ofl such dust removers, whether they be stationaryor rotary, may be improved by ionization of the dust particles inthe-conventional manner.

The dust may be discharged from the hoppers of the pressure vessel ofFig. l0 either through a conventional lock chamber or with the aid ofthe device about to be described.

In Fig. 10, the dust falls from each hopper 24 through pipes 26 intowhich respectively water is forced by a pump 21 through pipe 31 andbranches 38, 39. The dust mixes with the water and the resulting quiteuid sludge is collected in a tank 28 which is subjected through pipes 26to the pressure prevailing in the dust remover and is constructed towithstand this. pressure. Owing to this pressure, the sludge may becontinuously discharged to the atmosphere through a pipe 29. Thesectional area of the pipel 29, however, is so chosen that the rate offlow therethrough is not so great as to cause a reduction in thepressure Within the-pressure vessel and in the tank 28 and on the otherhand is suicient for continuous discharge of the sludge as it is formedwithout clogging of the pipe. YWithout requiring an excessive length ofthe pipe-29 the sectional area of the pipe may be su'iciently restrictedto limit the ilow therethrough to maintain the pressure withoutdeveloping velocities in the pipe 29 which would cause excessive wear.The pressure drop necessary for dischargingA the sludge from the tankunder high'pressure to the atmosphere is accomplished, however, by therestriction of the area for ow through the pipe 29 and the water thusdischarged from the tank is replaced by the pump 29 which is capable lofdelivering this water against the pressure within the tank 29.` Suitablecontrol means controlling the delivery of the water to the tank may beused for keeping the water in thetank 2B substantially at a given leveltherein. Experience has shown that such a devicefor removal of the dustseparated within a pressure vessel is quite suitable for the purposes ofthe invention.

The invention is applicable to all kinds of gases and dust particles. Itis also applicable to the removal of liquid particles in suspension ingases or vapours.

The flow through the units may be horizontal, vertical or oblique in thedifferent embodiments provided the hoppers are suitably arranged inrelation to the passages between the channels of the units so as tocollect the material separated from the gas in these passages due Atoreversal .of the flow therein. Y

1. Apparatus for separating from a gas material suspended therein which'comprises a casing providing a separating chamber and having a gas inletopening at one side of said chamber and a gas outlet opening at theopposite side of said chamber, at least one particle removal unitsupported in said chamber providing a pair of narrow generally parallelchannels dened by a partition wall and twov outer walls generallyparallel thereto and spaced therefrom at opposite sides thereof, meansconducting the gas with said material suspended therein through saidinlet opening into 4said chamber for flow therethrough toward saidoutletopening, said walls vof said unit beingdisposed parallel to thedirection of ow from said inlet opening'toward said outlet opening,meanscooperating with said walls of said unit and with said casing forconning said gas to flow from said inlet opening through the channelbetween said partition wall and one of said outer walls of said unit andthen about an edge of said partition wall to flow reversely through theother channel between said partition wall'and the other outer Wall ofsaid unit, means cooperating with said walls of said unit and with saidcasing for withdrawing through said outlet opening the gas from saidother channel of said unit, means cooperating with said partition walland said outer walls of said unit for effecting discharge of thematerial suspended therein from said gas under the centrifugal force ofreversal of its flow in passing from the rst channel to said otherchannel, and means for collecting said material discharged and separatedfrom said gas for removal from said casing. l

2. Apparatus for separating from a gas material suspended therein whichcomprises a casing providing a separating chamber' and having a gasinlet opening at one side of said chamber and a gas outlet opening atthefopposite side of said chamber, at least one particle removal unitsupported in saidfchamber' providing a pair of narrow generally parallelchannels defined by a partition wall and two outer walls generallyparallel thereto and spaced therefrom at opposite sides thereof, meansconducting theV gas with said material suspended therein through saidinlet opening into said'y chamber for now therethrough toward saidoutlet therefrom, said walls of saidvunit being disposed parallel to thedirection of flow from said inlei-l opening toward said outlet opening,a barrier wall spanning across at least one of said channels kandcooperating with said partition and outerwalls of said unit and withsaid casing to confine the gas from said inlet opening to flow lthroughone of said channels and to reverse its ow about an edge of saidpartition wall and to iiow reversely through the other channel towardsaid outlet from said chamber, said barrier Wallpreventing flow of thegas between said channels aboutsaid partition wall diverging fromfsaidflow of said gas along said iirst channel and then reversely along saidother channel, means cooperating with said partition wall and said outerwalls of said unit for effecting discharge of the material suspendedtherein from said gas as reversal of its iow is effected in passing fromsaid rst channel to said other channel, and means for collecting saiddischargedA initially suspended material for removal from said casing.

3. Apparatus for separating from a gas material suspended thereinwhichcomprises a casing providing a separating chamber and having' a gasinlet opening at one side vof said chamber and a gas outlet opening at'the opposite side of said chamber, at least one particle removal unitsupported in said chamber'providing a pair of narrow generally parallelchannels dened by a partition wall and two outer walls generallyparallel thereto and spaced therefrom at opposite sides thereof, meansconducting the gas with said material suspended therein through saidinlet opening into said chamber for flow therethrough toward said outlettherefrom, said walls of said unit being disposed parallel to thedirection oi flow fromvsaid inlet opening toward said outlet opening, -abarrier wall extending transversely of said partition wall andcooperating therewith and with one of said outer Walls of said unit andwith said casing to corinne said gas from said inlet opening to flowvdirectly into one of said channels to flow therealong and to preventflow of said gas directly into said other channel, a barrier Wallextending transversely of said partition wall and cooperating therewithand with the other outer wall of said unit to close the end of saidfirst channel disposed toward said casing outlet, said walls and saidcasing cooperating to coniine the gas to ow along said first channel andto be reversed about an edge of said partition wall and then to ow alongsaid other channel toward said outlet while being prevented from fiowingfrom said other channel back into said first channel, and meanscooperating with said partition Wall and said outer walls and saidcasing adjacent said edge of said partition wall for collecting materialinitially suspended in said gas and discharged therefrom as reversal ofits flow is effected about said edge of said partition wall.

4. Apparatus for separating from a gas material suspended therein whichcomprises a casing providing a separating chamber and having a gas inletopening at one side of said chamber and a gas outlet opening at theopposite side of said chamber, a plurality of generally parallelpartition walls supported in said chamber in spaced relation to eachother,means for conducting the gas with said material suspended thereinthrough said inlet opening into said chamber for flow therethroughtoward said outlet opening, said partition walls being disposed parallelto the direction of flow from said inlet opening toward said outletopening, barrier walls disposed with respect to said partition wallstoward said inlet and extending transversely of said partition wallsacross the alternate channels therebetween to prevent entrance oi saidgas into said barriered channels, said partition walls cooperating withsaid casing and said barrier walls to coniine said gas to flow into theother unbarriered channels between said partition walls and to flow inparallel paths therealong, means for conveying said gas from said outletopening of said casing, barrier walls extending transversely of saidpartition walls across said channels into which said gas flows at theends thereof disposed with respect to the gas flow toward said conveyingmeans While leaving open at the ends thereof disposed toward saidconveying means said channels barriered adjacent said gas inlet, saidcasing cooperating with said partition walls and said barrier walls toprovide passages communicating between adjacent channels to produce flowof said gas along the channels into which said gas flows from said inletand thereafter flow of said gas along said alternate channels to bedischarged therefrom to said conveying means, said passages being formedadjacent respective edges of the partition walls separating the channelsin which said gas ows in opposite directions for effecting sharpreversal of said flow about said edges and separation by centrifugalforce in said passages from said gas of said material suspended therein,and means cooperating with said casing and said partition walls and saidbarrier walls for collecting the material initially suspended in saidgas and separated therefrom in said passages.

5. Apparatus for separating from a gas material suspended thereinasfdeflned in claim 4 in which said partition walls are arranged inparallel planes vand are of generally right angle triangular shape insaid planes with the hypothenuse edges thereof extending at aninclination to the flow of the gas entering said casing and with theother edges of said triangles respectively parallel to and at rightangles to said entering flow, said transverse barrier walls which aredisposed toWard one of said openings of said casing extending along saidhypothenuse edges of said partition Walls, said barrier walls disposedt0- ward the other opening of said casing extending along said edges ofsaid partition walls which are at right angles to said entering flow ofsaid gas,rsaid casing cooperating with said partition walls and saidbarrier walls to form said passagescommunicating between adjacentchannels adjacent the respective edges of said partition walls whichextend parallel to the entering flow of said gas into said chamber,whereby said gases entering said chamber are ccnned to turn and to flowthrough alternate channels generally at right angles to said enteringnow and then to turn sharply about said edges which extend parallel tosaid entering iiow and thereafter to ow reversely through said otherchannels and again to turn generally at right angles to the ow in saidother channels toward said outlet opening and said means for conveying'said gas from said casing. j

6. Apparatus for separating from a gas material suspended" therein asdefined in claim 1 in which said casing is constructed as a pressurevessel capable of confining gas at substantial pressure therein, saidunit being supported within said pressure vessel, said means forcollecting said discharged and separated material for removal from saidcasing being connected to means adapted to effect said removal whilecooperating with said casing to confine said gas under pressure withinsaid pressure vessel.

'1. Apparatus for separating from a gas material suspended therein asdefined in claim 6, said means for eecting removal of said dischargedseparated material comprising a tank connected to said collecting meansand to said pressure vessel to receive the discharged separated materialwhile subjected to said pressure, means for delivering liquid underpressure to said tank for mixture therein with said separated material,and means for discharging said mixture of said liquid and said separatedmaterial continuously from said tank while maintaining said pressure ofsaid gas within said tank and said pressure vessel.

8. Apparatus for separating from a'gas material suspended therein asdened in claim 2 which comprises a plurality of said units arrangedwithin said casing for flow of said gas in series therethrough, saidpartition and outer walls in each unit having generally parallel edgesinclined with respect to the direction of gas ow through said unit, saidbarrier wallsI being inclined along said edges, said edges in adjacentunits being inclined in the same direction with respect to the directionof the gas flow through said casing.

9. Apparatus for separating from a gas material suspended therein asdefined in claim 2 which comprises a plurality of .said units arrangedwithin said casing for flow f said gas in series therethrough, saidpartition and outer walls in each unit having generally parallel edgesinclined with respect to the direction of gas iiow through said unit,said barrier walls being inclined along said edges, said edges inadjacent units being inclined in opposite directions with respect to thedirection of the gas iiow through said casing.

10. Apparatus for separating from a gas material suspended therein whichcomprises a casing providing a separating chamber, a member rotatablewithin said chamber constructed to provide a passage for ow of gastherethrough from an inlet opening thereof disposed generally centrallywith respect to the axis of rotation to an outlet opening thereofdisposed generally centrally with respect to said axis of rotation, aparticle removal unit carried by said rotatable member and cooperatingtherewith to conne said gas to ow therethrough from said inlet to saidoutlet opening of said member, said particle removal unit; beingconstructed with a generally radially extending partition wall betweentwo outer walls generally parallel to said partition Wall and disposedat opposite sides thereof in spaced relation thereto to provide a pairof narrow channels extending generally radially with respect to saidaxis of rotation, said walls being formed in relation to each other andto said rotatable member to provide a flow reversing passage disposedradially outwardly of and providing communication between said twochannels and communicating outwardly with said chamber, said partitionand outer walls cooperating With said rotatable member and with saidcasing to confine said gas to flow from said inlet opening into one ofsaid channels and to iiow radially outwardly in said channel and to iiowthrough said outwardly disposed iiow reversing passage and radiallyinwardly in said other channel to said outlet opening of said rotatablemember, means for rotating said rotatable member to produce the actionof centrifugal force on the material suspended in said gas to cooperatewith the centrifugal force produced by f reversal of said gas ilow insaid outwardly disposed fiow reversing passage for effecting separationof said suspended material from said gas and discharge thereof outwardlyinto said chamber, and means cooperating with said 10 chamber forcollecting and removing said material separated from said gas.

11. Apparatus for separating from a gas material suspended therein asdeiined in claim 10 which comprises a plurality of said particle removalunits carried by said rotatable member and disposed symmetrically aboutsaid axis of rotation.

12. Apparatus for separating from a gas material suspended therein asdened in claim 10 in which saidV outlet opening of said member isdisplaced along the axis of rotation from said inlet opening, wherebythe gas ows from said inlet opening generally along said axis ofrotation to said outlet opening.

13. Apparatus for separating from a gas material suspended therein asdefined in claim 10 in which said partition wall of said unit isconnected by a barrier wall to a Wall of said rotatable member toseparate the gas flowing from said inlet opening into said channel toflow radially outwardly therein from the gas flowing radially inwardlyin said other channel to said outlet opening.

14. Apparatus for separating from a gas material suspended therein asdefined in claim 1 in which said particle removal unit is provided witha member supported for reciprocating movement thereof in the directionparallel to said partition and said Walls of said unit and adjacent saidedge of said partition wall about which said gas iiows into said otherchannel, said member being provided with fingers respectively extendinginto said channels for cleaning said channels of particles deposited onsaid partition wall and said two outer Walls of said unit.

15` Apparatus for separating from a gas material suspended therein asdefined in claim 1 which comprises means for withdrawing from saidchamber a portion of the gas adjacent said edge of said partition wallabout which the ow of said gas is reversed and for delivering saidwithdrawn portion to the casing adjacent the inlet opening into saidchamber.

ERNEST MERCIER. MARCEL EHLINGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,267,297 West May 21, 19182,199,015 Toensfeldt Apr. 30, 1940 2,216,664 Fremd Oct. 1, 1940 FOREIGNPATENTS Number Country Date 554,289 Great Britain June 28, 1943

